The present invention relates generally to devices and methods for collecting and filtering biological suspensions. More specifically, the present invention relates to containers and methods for filtering bone marrow.
Bone marrow transplantation is used to treat a variety of hematological diseases. It is an accepted mode of therapy for a plastic anemia and immunodeficiency diseases. Additionally, bone marrow transplantation has been used experimentally to treat disorders such as refractory leukemias, metabolic diseases, congenital anemias, and malignancies.
Typically, bone marrow is removed in a sterile operating field using syringes and special aspiration needles while the donor is under general anesthesia. The marrow is collected from the sternum or iliac crest of the donor. The harvested marrow is then placed into a container and mixed with an anticoagulant solution.
After the marrow has been collected and combined with an anticoagulant, the mixture is then passed through two or more filtering devices to remove large particulate such as fat, bone chips, and/or clots. Originally, such filtering devices were "homemade" devices, for example, created using sawed-off glass or syringes to which wire screens were attached. After being filtered, the bone marrow cells are collected in a blood transfer pack unit and then transferred to the recipient or further processed per institutional procedure.
A few years ago, a bone narrow kit was developed by Baxter Healthcare Corporation, Deerfield, Ill. (a wholly owned subsidiary of the assignee of the present invention). The Fenwal Bone Marrow Kit, Code 4R2104, consists of a collection bag, three disk-shaped, rigid, stainless steel filters (500, 300, and 200 .mu.m sizes), and a final collection bag for the processed marrow. The kit allows users to perform the bone marrow processing methods set forth above in a standardized system that is sterile, disposable, and easy to use.
At times, it is possible for the filters in a bone marrow kit to become plugged due to bone chips, fat, and other cellular materials. Because of the rigid construction of the inline filter, it is necessary for the filter to be removed from the system and then flushed to remove the material plugging the filter. When this occurs, there exists a potential for contamination and loss of cells. Additionally, flushing the system has the additional disadvantage that it can dilute the marrow.